Axial flow cylinder of pneumatic tool

ABSTRACT

An axial flow cylinder of pneumatic tool, including: a cylinder body formed with an internal cylinder chamber; a rotary shaft rotatably disposed in the cylinder chamber along an axis of the cylinder body; and a predetermined number of movable wheels and fixed wheels mounted in the cylinder chamber. Multiple oblique first vents are annularly formed on each movable wheel at equal intervals. Multiple oblique second vents are annularly formed on each fixed wheel at equal intervals. The first and second vents are inclined in reverse directions. The movable wheels and the fixed wheels are interlaced with each other. The fixed wheels are fixedly disposed in the cylinder chamber without possibility of rotation. The movable wheels are synchronously rotatable with the rotary shaft. After high-pressure air flows from the intake into the cylinder chamber, the movable wheels and rotary shaft are driven and rotated by the high-pressure air. The air flows along the axis of the cylinder body between the vents of the movable wheels and fixed wheels and then is exhausted from the exhaust ports. In operation, the vents of the cooperative movable wheels and fixed wheels compress the air.

BACKGROUND OF THE INVENTION

The present invention is related to a pneumatic tool, and more particularly to an axial flow cylinder of a pneumatic tool. The axial flow cylinder has cooperative movable wheels and fixed wheels for compressing the air so as to provide high rotational speed and high power output.

FIG. 1 shows the pneumatic cylinder of a conventional pneumatic tool. An eccentric rotor 14 is mounted in the cylinder body 12 of the pneumatic cylinder 10. The high-pressure air flows from the intake 15 into the cylinder to drive the vanes 16 of the rotor to make the rotor rotate. Then the high-pressure air is exhausted from the exhaust port 17. Each two adjacent vanes of the rotor define a space. After flowing into the cylinder body, the high-pressure air goes into the equal-pressure area of a first position A. When rotating to a second position B, the capacity of the space is enlarged so that the air pressure is reduced. When rotating to a third position C, the capacity is further enlarged so that the air pressure is further reduced. In a fourth position D, the air is exhausted from the exhaust port 17. The fifth position E is a compression area. The rotational torque is produced by the pressure difference between position A and position E. The compression ratio of such pneumatic cylinder is about 15:1.

The above cylinder with eccentric rotor pertains to single-cylinder type. The highest pressure value in the cylinder body is the pressure value of the high-pressure air. Therefore, the output power of such type of pneumatic cylinder is limited. The rotational speed at most is about 10000 rpm and can be hardly enhanced.

The vanes 16 are slidably mounted in the vane slits 18 of the rotor. By means of the centrifugal force, the outer ends of the vanes keep in contact with the wall of the cylinder body 12. However, the vanes 16 repeatedly slide within the vane slits 18 to increase the friction in operation. Also, the outer ends of the vanes contact with the wall of the cylinder body to also create a frictional resistance. These frictional resistances will affect the rotation of the rotor to reduce the rotational speed and output of the pneumatic cylinder.

In order to reduce the frictional resistance, the wall, vane slits and vanes of the cylinder body are all manufactured at precision so that the manufacturing cost is relatively high.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide an axial flow cylinder of pneumatic tool. Several movable wheels and fixed wheels are disposed in the cylinder chamber of the cylinder and interlaced with each other. The air flows along the axis of the cylinder body between the vents of the movable wheels and fixed wheels to be compressed for increasing output power and rotational speed of the cylinder.

The present invention can be best understood through the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective sectional view of a pneumatic cylinder of a conventional pneumatic tool;

FIG. 2 is a perspective sectional view of a preferred embodiment of the present invention;

FIG. 3 is a partially sectional view according to FIG. 2;

FIG. 4 is a rear perspective partially sectional view according to FIG. 2;

FIG. 5 is a side sectional view according to FIG. 2;

FIG. 6 is a rear perspective view of the air-conducting member of the preferred embodiment of the present invention;

FIG. 7 is a perspective view of the movable wheel of the present invention;

FIG. 8 is a sectional view taken along line 8-8 of FIG. 5;

FIG. 9 is a perspective view of the fixed wheel of the present invention;

FIG. 10 is a sectional view taken along line 10-10 of FIG. 5;

FIG. 11 is a perspective sectional view of another preferred embodiment of the present invention;

FIG. 12 is a perspective exploded view of a part of the components of FIG. 11, showing the rotary shaft and a set of movable wheel and fixed wheel; and

FIG. 13 is a rear perspective assembled view according to FIG. 12.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 2 to 4. The pneumatic cylinder 20 of the present invention includes a cylinder body 30 and multiple movable wheels 60 and fixed wheels 70 interlaced with each other and disposed in the cylinder body 30. The movable wheels are rotatable along with a rotary shaft 50. The movable wheels and the fixed wheels serve to compress the air to create a boosting effect for enhancing the output power and rotational speed of the pneumatic cylinder.

The cylinder body 30 of the preferred embodiment is composed of three block bodies, that is, a front block body X, a middle block body Y and a rear block body Z. The front end of the cylinder body is formed with an intake 32. A cylinder chamber 34 is formed in the cylinder body. After the high-pressure air flows into the intake 32, the air can flow through a flow way 35 into the cylinder chamber 34. Then the air is exhausted from one or more exhaust port 38 of rear end of the cylinder body as shown in FIG. 4. An annular cavity 36 is formed in the cylinder body 30 on front wall face of the cylinder chamber 34 as shown in FIG. 5.

Referring to FIG. 6, an annular air-conducting member 40 has twenty-five air-conducting holes 42 annularly formed on the air-conducting member 40 at equal intervals. The air-conducting holes pass through the air-conducting member from a front end face to a rear end face. Each air-conducting hole 42 and the axis of the air-conducting member contain a 30 degree angle. Referring to FIGS. 3, 5 and 6, the air-conducting member 40 is mounted and located in the cavity 36 by the head sections of three screws 45 engaged with three dented sections 44 of rear end face of the air-conducting member.

The rotary shaft 50 is mounted in the cylinder body 30 and fitted through two bearings 52 disposed in the cylinder body. A rear end of the rotary shaft extends out of the cylinder body.

In this embodiment, there are six sets of movable wheels 60 and fixed wheels 70.

Referring to FIG. 7, twenty-five first vents 62 are annularly formed on each movable wheel at equal intervals. The first vents 62 pass through the movable wheel from a front end face to a rear end face thereof. The axis of each vent 62 and the axis of the movable wheel contain a 30 degree angle. The movable wheel 60 has a central through hole 64 through which the rotary shaft 50 is fitted. The through hole 64 has a key notch 66 in which a key 54 of the rotary shaft is inserted as shown in FIG. 8. Accordingly, the movable wheel 60 is synchronously rotatable with the rotary shaft.

Referring to FIG. 9, the fixed wheel 70 is ring-shaped. Twenty-five second vents 72 are annularly formed on each fixed wheel at equal intervals. The axis of each vent 72 and the axis of the fixed wheel contain a 45 degree angle. In addition, the vent 72 of the fixed wheel is inclined in a direction reverse to a direction in which the vent 62 of the movable wheel is inclined. For example, the vents 62, 72 can be inclined from the tangent T to different sides. Alternatively, the vents 62, 72 can be inclined from the normal N to inner or outer side. The fixed wheels are fixedly disposed in the cylinder chamber 34 at equal intervals without possibility of rotation. The fixed wheels and the movable wheels are interlaced with each other. The rotary shaft extends through a through hole 74 of the fixed wheel.

Referring to FIGS. 5 and 10, in the embodiment, the fixed wheel is fixed in such a manner that three elongated bolts 75 are inserted in three longitudinal slots 76 of the cylinder wall and three dents 78 formed on outer circumference of the fixed wheel 70. Referring to FIGS. 4 and 10, six inner spacing plates 80 are fitted on the rotary shaft at equal intervals and synchronously rotatable with the rotary shaft and the movable wheels. The inner spacing plates 80 are positioned in the through holes 74 of the fixed wheels 70. Each inner spacing plate 80 has a thickness slightly larger than the thickness of the fixed wheel. The movable wheels 60 and the inner spacing plates 80 are leant on each other, whereby the movable wheels are kept at equal intervals. Also, the thickness of the inner spacing plate 80 is larger than the thickness of the fixed wheel so that the gap between two adjacent movable wheels 60 is larger than the thickness of the fixed wheel. Therefore, the movable wheel will not contact with the fixed wheel. The diameter of the inner spacing plate is slightly smaller than that of the through hole 74 of the fixed wheel so that the fixed wheel and the inner spacing plate will not contact with each other. Referring to FIGS. 4 and 8, six annular outer spacing plates 85 are interlaced with the fixed wheels. Each outer spacing plate 85 has a thickness slightly larger than the thickness of the movable wheel 60. The inner diameter of the outer spacing plate 85 is slightly larger than the outer diameter of the movable wheel 60. The outer spacing plates and the fixed wheels are leant on each other to keep the fixed wheels at fixed intervals. Accordingly, when the cylinder operates, the components thereof will not abrade each other.

After the rotary shaft with the movable wheels and fixed wheels is mounted into the cylinder body, a first movable wheel 60 a is positioned behind the air-conducting member 40. The air-conducting hole 42 is inclined in a direction reverse to the direction in which the vent 72 of the first movable wheel is inclined.

In use, the high-pressure air flows from the intake 32 into the cylinder chamber 34 and flows along the axis of the cylinder body and then flows out from the exhaust ports 38.

Referring to FIGS. 3 and 4, the high-pressure air flows through the flow way 35 into the annular cavity 36 and then flows out from the 25 air-conducting holes 42 of the air-conducting member 40. The air-conducting holes 42 serve to conduct the airflow to obliquely flow toward the first movable wheel 60 a and then flow into the vents 62 thereof. The airflow obliquely flowing out from the air-conducting holes provides kinetic energy for driving the first movable wheel 60 a, whereby the first movable wheel is rotated in a direction of arrow F of FIG. 3. The rotary shaft 50 and the other movable wheels are synchronously rotated with the first movable wheel.

When the air flows within the vents 62 of the first movable wheel 60 a, an oblique airflow is produced. After flowing out of the vents 62, the air flows into the vents 72 of the first fixed wheel 70 a. The air obliquely flows within the vents 62, 72 of the first movable wheel 60 a and first fixed wheel 70 a in different directions. Therefore, in operation, when the high-pressure air flows from the position of the vents of the first movable wheel 60 a into the position of the vents of the first fixed wheel 70 a, due to change of the direction of the airflow and the variation of the capacity of the vents 62, 72 taking place when the movable wheel rotates, the air is aerodynamically compressed between the vents 62, 72. Such compression is a first-grade compression.

After the compressed airflow flows out from the first fixed wheel 70 a, the airflow continuously flows toward the second movable wheel 60 b. After passing through the vents 62 of the second movable wheel 60 b and the vents 72 of the second fixed wheel 70 b, which vents are inclined in different directions, the airflow is further compressed to form a second-grade compression. Then, the compressed airflow further flows through the third movable wheel 60 c and third fixed wheel 70 c to be third-grade compressed. Accordingly, the compressed airflow continuously flows to the sixth movable wheel 60 f and sixth fixed wheel 70 f to be sixth-grade compressed. Eventually, the air is exhausted from the exhaust ports 38 of the cylinder body.

Each set of movable wheel and fixed wheel form a compression area. Each grade of compression serves as a cylinder to compress the air. Therefore, the air is six-grade compressed from the initial pressure like the air is continuously compressed by six cylinders to achieve a final pressure value. The pressure value is the product of the six-grade compression. Presuming that the initial air pressure is 2 psi, then 2 psi×1=2 psi (through first-grade compression), 2 psi×2=4 psi (through second-grade compression), 4 psi×3=12 psi (through third-grade compression), 12 psi×4=48 psi (through fourth-grade compression), 48 psi×5=240 psi (through fifth-grade compression) and 240 psi×6=1440 psi (through sixth-grade compression). After the six-grade compression, the air pressure value is 720 times enlarged. Therefore, the present invention can greatly increase the pressure of the air to achieve high output power and high rotational speed. The rotational speed of the conventional cylinder is about 6000˜7000 rpm. Through a simple test of the model of the present invention, the rotational speed of the present invention can easily reach over 25000 rpm.

In this embodiment, the vents 62 have a length equal to that of the vents 72. Therefore, in each grade of compression, the movable wheel and fixed wheel compress the air in a stabilized state. The vents can be inclined straight vents or inclined arched vents.

FIG. 11 is a partially sectional view showing another embodiment of the cylinder 90 of the present invention, in which the intake of the most front end of the cylinder body 100 is not shown. In the block bodies forming the cylinder body, the most front block body P is made by injection molding and formed with an annular cavity 102. In addition, multiple oblique vanes 104 are integrally formed on rear side of the cavity and annularly arranged at equal intervals. Each vane 104 is a straight plate or an arched plate. Each two adjacent vanes define an oblique air-conducting hole 106. After flowing into the annular cavity 102, the high-pressure air is conducted by the air-conducting holes 106 to obliquely flow into the cylinder chamber for driving the movable wheels and rotary shaft 110 to rotate.

Referring to FIG. 12, in this embodiment, the movable wheels 120 and the fixed wheels 130 are annular plate bodies made by punching or injection molding.

The end face of each movable wheel 120 is formed with multiple openings 122 annularly arranged at equal intervals. An oblique vane 124 rearward extends from one side of each opening. Each two adjacent vanes define an oblique first vent 126. The axis of the vent 126 and the axis of the movable wheel contain a 30-degree angle.

Similarly, the end face of each fixed wheel 130 is formed with multiple openings 132 arranged at equal intervals. An oblique vane 134 rearward extends from one side of each opening. Each two adjacent vanes define an oblique second vent 136. The axis of the vent 136 and the axis of the fixed wheel contain a 45-degree angle. The vents 126 of the movable wheel and the vents 136 of the fixed wheel are inclined in different directions.

An inner spacing plate 140 is fixedly connected with inner circumference of each the movable wheel 120. The inner spacing plate 140 has a hexagonal hole 142 in which the rotary shaft 110 is fitted. The inner spacing plate is synchronously rotatable with the rotary shaft.

The front and rear end faces of each fixed wheel 130 are clamped by outer spacing plates 145 and fixed in the cylinder chamber. The inner spacing plate 140 has a thickness larger than the thickness of the movable wheel and fixed wheel. Therefore, when the fixed wheels and movable wheels are interlaced with each other, the inner spacing plate slightly protrudes from the through hole 138 of the fixed wheel. When two adjacent inner spacing plates 140 are leant on each other, not only the movable wheels 120 are kept at equal intervals, but also a gap is defined in which the fixed wheel 130 is located without touching the movable wheel and the inner spacing plate. Also, the outer spacing plate 145 and the movable wheel will not touch each other.

In use, the high-pressure air is conducted by the air-conducting holes 106 to form oblique airflow flowing into the cylinder chamber. The airflow provides kinetic energy for driving the first movable wheel 120 a, whereby the rotary shaft 110 and the movable wheels are synchronously rotated.

After the air flows through the vents 126, 136 of the first movable wheel 120 a and the first fixed wheel 130 a, the air is first-grade compressed. The compressed airflow then sequentially flows along the axis of the cylinder body 100 through the successive sets of movable wheels and fixed wheels. After reaching the final sixth movable wheel 120 f and sixth fixed wheel 130 f, the six-grade compression is accomplished. Eventually, the air is exhausted from the exhaust ports 108. Accordingly, high rotational speed and high power output of the rotary shaft 110 can be achieved.

In the cylinder of the present invention, the air flows along the axis of the cylinder body and the high-pressure air serves as the power source for the movable wheels and rotary shaft. The air is compressed by the cooperative movable wheels and fixed wheels to form multi-grade compression. After compressed grade by grade, the air pressure is gradually increased to achieve high power. The power output efficiency of the present invention is much higher than the conventional device. The number of the sets of the movable wheels and fixed wheels is not limited. For example, there can be six sets of movable wheels and fixed wheels to achieve six-grade compression. Alternatively, there can be three sets of movable wheels and fixed wheels to achieve three-grade compression.

In operation, the components of the present invention will not abrade each other so that the frictional resistance can be reduced to reduce power loss.

The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention. 

1. An axial flow cylinder of pneumatic tool, comprising: a cylinder body formed with an internal cylinder chamber; a front end of the cylinder body being formed with at least one intake; a cavity being formed at the front end of the cylinder body between the cylinder chamber and the intake, the intake, the cavity and the cylinder chamber communicating with each other; multiple oblique air-conducting holes being annularly disposed in the cavity at equal intervals; a predetermined number of exhaust ports being formed at a rear end of the cylinder body and communicating with the cylinder chamber; a rotary shaft rotatably disposed in the cylinder chamber along an axis of the cylinder body; a predetermined number of movable wheels mounted on the rotary shaft at equal intervals and synchronously rotatable with the rotary shaft; multiple first vents being annularly formed on each movable wheel at equal intervals, an axis of each first vent and an axis of the movable wheel containing a predetermined angle; a first movable wheels being positioned behind the air-conducting holes; the air-conducting holes corresponding to the first vents, the air-conducting holes being inclined in a direction reverse to the direction in which the first vents being inclined; and multiple fixed wheels the number of which is equal to the number of the movable wheels, multiple second vents being annularly formed on each fixed wheel at equal intervals, an axis of each second vent and an axis of the fixed wheel containing a predetermined angle, the fixed wheels being fixedly disposed in the cylinder chamber without possibility of rotation, the fixed wheels and the movable wheels being interlaced with each other, the second vents being inclined in a direction reverse to a direction in which the first vents are inclined; whereby after high-pressure air flows from the intake into the cylinder chamber, the movable wheels and rotary shaft are driven and rotated by the high-pressure air, the air flowing along the axis of the cylinder body between the vents of the movable wheels and fixed wheels and then being exhausted from the exhaust ports.
 2. The axial flow cylinder as claimed in claim 1, wherein the movable wheels and fixed wheels are ring-shaped bodies, the first vents passing through the movable wheel from a front end face to a rear end face thereof; the second vents passing through the fixed wheel from a front end face to a rear end face thereof.
 3. The axial flow cylinder as claimed in claim 2, wherein an axial key is formed on the circumference of the rotary shaft; an inner circumference of each movable wheel being formed with a key notch in which the key of the rotary shaft is inserted; the cylinder further comprising a predetermined number of inner spacing plates fitted on the rotary shaft interlaced with the movable wheels, the movable wheels and the inner spacing plates being leant on each other, whereby the movable wheels are kept at equal intervals; the fixed wheel having an inner diameter larger than an outer diameter of the inner spacing plate.
 4. The axial flow cylinder as claimed in claim 3, further comprising a predetermined number of outer spacing plates disposed on a wall of the cylinder chamber; outer circumferences of the fixed wheels being located by the outer spacing plates and kept at equal intervals.
 5. The axial flow cylinder as claimed in claim 1, wherein the movable wheels and the fixed wheels are annular plate bodies, an end face of each movable wheel being formed with multiple openings annularly arranged at equal intervals, an oblique vane rearward extending from one side of each opening, each two adjacent vanes defining a said first vent; an end face of each fixed wheel being formed with multiple openings arranged at equal intervals, an oblique vane rearward extending from one side of each opening, each two adjacent vanes define a said second vent.
 6. The axial flow cylinder as claimed in claim 5, further comprising multiple inner spacing plates the number of which is equal to the number of the movable wheels, each inner spacing plate being an annular body, the inner spacing plates being fitted on the rotary shaft along the axis of the rotary shaft at equal intervals and synchronously rotatable with the rotary shaft; the inner circumference of the movable wheel being fixedly connected with the inner spacing plate.
 7. The axial flow cylinder as claimed in claim 6, further comprising a predetermined number of outer spacing plates disposed on a wall of the cylinder chamber; the outer circumferences of the fixed wheels being fixed by the outer spacing plates.
 8. The axial flow cylinder as claimed in claim 1, further comprising an air-conducting member disposed in the cavity; the air-conducting holes being formed through the air-conducting member from a front end face to a rear end face thereof.
 9. The axial flow cylinder as claimed in claim 1, wherein multiple vanes are disposed in the cavity at equal intervals, each two adjacent vanes defining one of the air-conducting holes.
 10. The axial flow cylinder as claimed in claim 1, wherein the first vent has a length equal to a length of the second vent.
 11. The axial flow cylinder as claimed in claim 1, wherein the vents are oblique straight vents.
 12. The axial flow cylinder as claimed in claim 1, wherein the vents are oblique arched vents.
 13. The axial flow cylinder as claimed in claim 1, further comprising a flow way formed at the front end of the cylinder body to communicate with the intake and the cavity.
 14. The axial flow cylinder as claimed in claim 1, wherein two bearings are respectively disposed at the front and rear ends of the cylinder body, the rotary shaft being fitted in the bearings. 